Start Discovering Solved Questions and Your Course Assignments
TextBooks Included
Active Tutors
Asked Questions
Answered Questions
q explain about error detectiondata can be corrupted during transmission because of accidents storms sudden increase in electricity and voltage
q explain about flow control- signifies to ask the transmitter to stopresume sending in data- required when dte to dce speed gt dce to dce speed -
q show the function of signals- td transmitted data- rd received data- dsr data set ready indicate whether dce is powered on - dtr signifies data
q mechanical characteristics of rs232 interface- 9-pin connector- 9-pin connector is more usually found in ibm-pc but it covers signals for
q define rs232 interface- indicates the interface between dte and dce v28 mechanical as well as electrical characteristics v24 functional as well as
q show v32 standard- itu-ts v32 standard was issued in 1991 for asynchronous and full-duplex operation at 144 kbps v32bis- is an extension of the v32
q define v - 32 modem- itu-ts v32 standard was issued in 1989 for asynchronous and full-duplex operation at 9600 bps- even though designed for
q what is bipolar encoding- uses three voltage levels negative positive and zero- zero level represents binary 0 1s are represented with alternating
q illustrate return to zero encoding- in nrz-i long strings of 0s may still be a problem- may comprise synchronization as part of the signal for both
q show nonreturn to zero encoding- value of signal is for all time positive or negative- nrz-l signal level depends on bit represented positive
q what is cross over cable- cross the critical pair to properly transmit align and receive signals on devices with like connections- pin 1 connected
q straight through lan cable straight through cable - maintain the pin connection each the way through the cable- the wire connected to pin 1 is the
q show ethernet media standard- the cables and connector specifications utilized to support ethernet implementations are derived from the eiatia
q show infrared applications- wide bandwidth accessible for data transmission- communication between mice pcs keyboards and printersmedia selection -
q use of infrared- frequencies among 300 ghz and 400 thz- short-range communication- high frequencies cant penetrate walls- necessitate line-of-sight
q microwave applications- unicasting - one-to-one communication among sender and receiver- cellular phones- satellite networks- wireless
q show the properties of microwavesmicrowaves - frequencies among 1 and 300 ghz- unidirectional- narrow focus requires sending as well as receiving
radio waves - frequency ranges 3 khz to 1 ghz- omni directional- susceptible to interference by other antennas utilizing same frequency or band-
disadvantages of fiber optics - installationmaintenance- unidirectional-
q advantages of fiber optics- higher bandwidth in comparison to twisted-pair and coaxial cable is not limited by medium but by equipment used to
applications of fiber optics - backbone networks because of wide bandwidth and cost effectiveness- cable tv- lans- 100base-fx fast
- light source is led light-emitting diode or a laser- leds are cheaper however not as precise unfocused limited to short-distance use- lasers is
q single mode for transmitting optical signals- merely one beam from a light source is transmitted using a smaller range of angles- smaller diameter
q what is multimode graded-index fiber- ever since the core density decreases with distance from the centre the light beams refract into a curve-
q multimode for transmitting optical signals- multiple beams from light source travel through core at different paths- multimode step-index fiber